Method of forming concrete piles in situ



July 16, 1963 H. c. sALAssl METHOD 0E Ecm/ENG CONCRETE PILES 1N sITU Filed March 20. 1961 United States Patent O 3,097,492 METHOD F FORMING CONCRETE PILES IN SITU Hugh C. Salass, 5733 College Drive, Baton Rouge, La. Filed Mar. 20, 1961, Ser. No. 96,356 4 Claims. (Cl. 61--36) This invention relates to a new and improved method of forming concrete piles in situ.

The advantages of forming concrete piles in situ yare widely recognized, particularly in instances where the required pile is of a relatively great length, and a suitable preformed pile would present relatively expensive and cumbersome handling problems. This is laptly illustrated in situations where a number of concrete piles are to be placed in a remote and generally inaccessible area.

Numerous methods have been advanced for forming concrete piles in situ. Such prior art methods generally employ such features as forcing pre-mixed grout through a hollow cylindrical tool placed within a hole; or, in instances where an auger is used in the pile-forming process, the auger is loperated to loosen the soil, and to some extent, to mix the soil with a pre-mixed binding agent.

While such prior :art methods have enjoyed varying degrees of success insofar as the desired end result is concerned, they generally require specially constructed tools such as hollow shafts :with unusual blade structures attached thereto. Additionally, the introduction of grout or the like under pressure into a hollow shaft necessitates special transporting and pumping equipment which further hampers prompt and convenient construction, as in remote areas.

An object of this invention is to provide la new and improved method of forming concrete piles in situ which is far simpler than heretofore known methods, which requires only use of conventional tools and equipment.

Another object [of this invention is to provide =a method of forming concrete piles in situ Vwherein a conventional `auger is used both for mixing and drilling; the cement, water, aggregate and the like being added for mixing by the auger with the sandy soil in the upper portion of the desired hole depth. In this regard the auger acts in the manner of the blade of a concrete mixer.

Still a further object fof the invention is to provide a method `of forming concrete piles in situ wherein a hole is drilled by an auger to a portion of the desired pile length, cement, water and other desired materials are added as such to this upper portion of the hole, and the auger is operated to continually raise sandy soil from below this area for mixing with the constituent materials, the material being added, and the auger raising and mixing the gravel until the desired pile length and consistency is obtained.

Further objects and advantages of this invention will become evident in the specification, claims, and the accompanying drawing.

FIGURES 1-5 show in vertical section la sequence of steps in constructing a concrete pile according to this invention.

At the pl-ace `where a concrete pile of predetermined length is to be formed, a hole is dug which is a fraction of the total length of the pile. For example, if a concrete pile 30 feet in length is to be formed and the desired mix composition is 1:2?1, the hole will be initially dug to a depth of about l()l feet. To this end, 'a standard auger is provided of a s-ize corresponding to the diameter of the pile and is mounted on any conventional earth drilling rig (not sho-wn). This portion `of the hole, `designated as L in FIGURES 1-4, provides a mixing chamber, as will become apparent.

After the hole is :drilled to the depth L, and while the auger is preferably still turning, water and cement are added to the hole L while the auger is lowered into the undisturbed sand, then raised, so that the sand, cement and water can be mixed by the auger. The auger is again lowered to `a point six or eight inches lower than before, and this unmixed sand is brought to the mixing area L and more water land cement are added, as necessary. This procedure is repeated until the auger has been drilled to the required depth.

yIt will be appreciated that the auger serves the dual function of a drilling tool and a mixing tool; and, after the auger has ldrilled and mixed the sand in the portion of the hole below the area L with the constituents added to the area L, the auger is raised and lowered from top to bottom several times to ensure a thorough mixing of cement, sand, and water. The contents of the hole thereby are in the form of well-mixed mortar.

Gravel, crushed stone and the like are conveniently added to the now formed ymortar as desired, and the rotating auger is raised and lowered until these materials are evenly distributed from top to bottom. As desired, reinforcing rods can be installed in the hole after the mixing `operation is completed.

Referring specially to the drawings, in

FIGURE l the auger 10 is shown during the initial drilling operation wherein a hole 12 is drilled to a depth L in the soil formation 14 and the sand is removed therefrom, this fraction of the ultimate hole depth serving as an initial mixing chamber. Cement `1-6 land] water are then added to the hole 12 and mixed with sand raised to this area by the rotating auger 10.

FIGURES 2-4 show the subsequent pile forming operation, wherein the auger 10l is continu-ally drilling into the' packed sand and raising the material to the upper region Lof the hole 12 for mixing with added cement and water, the mixed san-d, cement and water being indicated by the reference numeral 18. In FIGURE 4, the auger 10` is shown near the final stage `of the drilling operation, where the lowermost quantity of sand h-as just been drilled. This sand will then be raised upwardly -for mixing with the constituents added to the top of the hole 12. 'The entire length of the hole -12 will then be subjected to a nal mixing `operation by raising and lowering the riotating auger 1()` to provide a uniform consistency through- `out the length of the hole 12, adding gravel and aggregate if necessary or desired.

In FIGURE 5 the iinal uniformly mixed body of settable material is shown at 20, reinforcing rods 22 have been placed in the pile, and the structure is completed.

It Will be appreciated that, by virtue of forming the pile as described, the problem of introducing solids or semi-solids into the hole through a hollow shaft under pressure is `obviated. The operation is simple and utterly reliable, as the quantities of water, cement and the like to be added to the hole, as well as the amount of sand to initially remove, m-ay be readily calculated, depending on the size and composition of the pile desired. In this regard, the amount of water to be added will be determined by the water table in the particu-lar locale. Further, the only special equipment required at the scene is a conventional earth drilling rig with a suitable auger operably attached thereto.

Throughout the specification and claims the term sand Aor sandy soil is used in a liberal sense to signify a type :of soil that is adapted for mixing with cement and water or equivalent constituents to provide a pile structure.

It will thus be seen that the objects of this invention, together with many practical advantages, have been successfully accomplished.

It will be realized however, that the foregoing specific embodiment has been shown and described only for the purpose of illustrating the principles of this invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

I claim:

1. Method `of forming concrete piles in situ comprising the steps of: drilling a hole in sandy soil to a predetermined fraction of the ultimate pile depth and removing the soil therefrom, this hole constituting a mixing area; adding hydraulically settable cementitious material to the hole to form a uid concrete mix with the underlying soil; drilling to a slightly lower `depth into the underlying soil by means of a rotating auger and raising the newly drilled soil upwardly and mixing the newly drilled soil with the cementitious material thereabove by raising the rotating -auger into the mixing area; repeating said drilling, raising and mixing steps in a progressive operation until the predetermined depth of the pile is reached, whereby the newly drilled soil and the cementitious material are uniformly mixed throughout the entire depth by the rotating auger, and then removing the auger from the formed concrete pile.

2. Method according to claim 1, wherein coarse aggregate is added prior to removal of the auger, and is uniformly mixed throughout the entire depth of the pile by repeated raising and lowering of the rotating auger through the pile.

3. Method according to claim 1, including the subsequent step of inserting met-al reinforcing rods.

4. Method according to claim 1, wherein the cementitious material ladded is hydraulically settable cement and water.

References Cited in the le of this patent UNITED STATES PATENTS 935,081 Wolfsholz Sept. 28, 1909 1,189,108 Hildebrand June 27, 1916 2,048,710 Ranney July 28, 1936 2,326,045 McGonnaughay Aug. 3, 1943 2,729,067 Patterson Ivan. 3, 1956 2,782,605 Wertz et al. Feb. 26, 1957 3,023,585 Liver Mar. 6, 1962 FOREIGN PATENTS 237,929 Great Britain Nov. l2, 1925 

1. METHOD OF FORMING CONCRETE PILES IN SITU COMPRISING THE STEPS OF: DRILLING A HOLE IN SANDY SOIL TO A PREDETERMINED FRACTION OF THE ULTIMATE PILE DEPTH AND REMOVING THE SOIL THEREFROM THIS HOLE CONSTITUTING A MIXING AREA; ADDING HYDRAULICALLY SETTABLE CEMENTITIOUS MATERIAL TO THE HOLE TO FORM A FLUID CONCRETE MIX WITH THE UNDERLYING SOIL; DRILLING TO A SLIDABLY LOWER DEPTH INTO THE UNDERLYING SOIL BY MEANS OF A ROTATING AUGER AND RAISING THE NEWLY DRILLED SOIL UPWARDLY AND MIXING THE NEWLY DRILLED SOIL WITH THE CEMENTITIOUS MATERIAL THEREABOVE BY RAISING THE ROTATING AUGER INTO THE MIXING AREA; REPEATING SAID DRILLING, RAISING AND MIXING STEPS IN A PROGRESSIVE OPERATION UNTIL THE PREDETERMINED DEPTH OF THE PILE IS REACHED, WHEREBY THE NEWLY DRILLED SOIL AND THE CEMENTITIOUS MATERIAL ARE UNIFORMLY MIXED THROUGHOUT THE ENTIRE DEPTH BY THE ROTATING AUGER, AND THEN REMOVING THE AUGER FROM THE FORMED CONCRETE PILE. 